Isolated porthole, the only one in half a
mile, means life or death to the seal, who
must find it to breathe. Dr. Ray (left) be
lieves the animals use sonar, bouncing
voice signals off the ice to locate such pas
sageways. Constant use keeps the holes
open even in the coldest weather; the seals
enlarge them by sawing with their teeth.
Blubbery bodies smooth the edges.
Sleek as a bullet, an 800-pound Weddell
plunges through its hole in the ice. It sur
vives long (lives by constricting surface
blood vessels to ensure a steady suppl)ly of
blood to heart and brain. The Weddell
s
raalso
tolerates large amounts of carbon
dioxide in the blood. Thus it can remain
submerged for half an hour or longer, seek
ing food at depths as great as 1,500 feet
the deepest (live known for seals.
Flood-lansmp eyes peer from
the bucket-shaped capsule into
the undersea gloom as divers
like astronauts afloat in space
circle amid a swarm of air
bubbles. Light-reflecting paint
flakes off the suit of the diver
at right. Barring leaks in their
suits, the men can withstand
the 28.6
°
F. water for almost
an hour. Submerged 16 feet
below the icy surface, the ob
servation chamber gave team
members longer, more pro
tected sessions in the deep.
Scientists spent up)to two hours
in the cylinder despite temper
atures in the chilly 30's. Like a
submarine's periscope, the 12
foot access tube thrusts up
through the ice. Long struts
hold ballast for the six-foot
high compartment.
Around the hole "sunlight fil
tered through the ice as a bluish
haze that resembled a cloudy
sky," recalls D)r. Ray. "But dim
surface illumination rapidly
faded into blackness below."
EKTACHROME(ABOVE) AND DUOTONE (OPPOSITE) BY CARLETON RAY;
KODACHROME(TOP) BY DAVID0. LAVALLEE(c) N,G..S